INSECT PESTS OF OHIO SHADE AND FOREST TREES 213 



the opportunity exists to count the number of eggs in an egg mass, 

 the number of egg masses to the measure, and the number of 

 measures collected. All multiplied together give the sum total of 

 the eggs a truly astonishing number. Because of its magnitude 

 the fearful are quieted and after the shouting has subsided there is 

 a tendency to rest on the oars, without further effort. If such is 

 the result of the campaign more harm than good is done by it. 



When collecting is done during the winter, the egg masses in 

 no case should be destroyed. They should be spread out in wire 

 containers not closer than 100 feet to the nearest tree and left 

 remain until midsummer in order that the beneficial parasites may 

 have a chance to emerge. 



Banding the trees with mechanical barriers or with sticky sub- 

 stances is a common practice in cities. Under but one condition is 

 this practice of great value. If the banded tree is free from the 

 insect, and its branches do not interlock with infested or unpro- 

 tected ones, banding prevents the wingless moths or migrating 

 caterpillars from ascending the trunk and infesting the branches. 

 If the top is already infested with some stage of the insect, banding 

 is of little or no value. Again, banding would be of greater practical 

 usefulness if the probability did not exist that the very young cater- 

 pillars are dispersed by the wind, blowing from one treetop to the 

 next. When all these qualifying conditions are considered, it seems 

 questionable if banding really is worth while. Moreover, many 

 place complete dependence in the banding process, thus failing to 

 provide really effective assistance to the tree, and as a result, their 

 efforts are really harmful rather than useful. 



THE FALL WEfeWOEM 



(Hyphantria cunca Hub.) 



Description. Fall webworms are most frequently recognized 

 by the unsightly light-gray silken webs on the trees in the late sum- 

 mer and early fall (see Plate XX, Fig. 2), and by the blackened, 

 tangled web-remnants which Remain on the branches over winter 

 to detract from the appearance of the host. 



The parent form is a moth which varies considerably in color, 

 from pure white to white spotted with black. The eggs, deposited 

 on the underside of the leaf, occur in clusters of 1 to 300. They are 

 light yellow in color. (See Plate XX, Fig. 1, for illustrations of 

 life history stages.) 



The following description of the caterpillar is taken from the 

 Fifth Report of the United States Entomological Commission. 



